Electro-magnetic lifting magnets are commonly associated with cranes. Cranes with lifting magnets are utilized for manipulating relatively heavy magnetic materials, such as, for example, scrap steel, ferrous material, and the like.
In some situations/environments, a crane operator may willfully or unintentionally impart damage to the lifting magnet. For example, referring to FIG. 3, if an electric current is delivered, without interruptions, or, with shorts interruptions, the lifting magnet may not adequately cool down such that the temperature of lifting magnet steadily increases during the above-described period(s) when the lifting magnet is not provided with an adequate rest period. This increase in temperature of the lifting magnet, however, typically detracts from its magnetic strength; to compensate for this loss of magnetic strength, the operator may have to resort to increasing current flow to the magnet, which may solve the immediate problem by re-establishing the magnet's strength while concurrently increasing the likelihood of causing destruction to/failure of the lifting magnet should the magnet temperature exceed a critical temperature, TC.
Even further, if, for example, the crane operator moves the magnet in a manner that imparts high accelerations thereto, or, alternatively, a sudden, free-fall dropping movement of the magnet/the handled material, the end result may include a whipping of the crane's derrick and/or voltage spiking that is seen across the magnet.
If such willful/unintentional operation of the lifting magnet is conducted over a period of time, the damage imparted to the lifting magnet may result in financial loss and/or down-time of the operation of the crane in addition to the cost to repair the lifting magnet. Without a supervisor having knowledge of the willful/unintentional damage to the lifting magnet by a particular operator of the crane, it may be otherwise difficult to identify a particular operator that caused the damage, or, hold a crane operator accountable for the undesirable operation of the lifting magnet and crane that may eventually result in damage to the crane and/or magnet.
Accordingly, there is a need in the art for method and apparatus for providing diagnostics of a crane and/or lifting magnet.